Apparatus for controlling silt accumulation



March 14, 1950 F. R. HARRIS APPARATUS FOR CONTROLLING SILT ACCUMULATIONFiled Feb. 24, 1945 3 Sheets-Sheet l Z zw/we ATTORNEY.

March 14, 1950 F. R. HARRIS 2,500,354

APPARATUS FOR CONTROLLING SILT ACCUMULATION Filed Feb. 24, 1945 sSheets-Sheet 2 F reden'c' I ff arr/1s ATTORNEY.

March 14, 1950 F. R. HARRIS 2,500,354

APPARATUS FOR CONTROLLING sm ACCUMULATION Filed Feb. 24, 1945 3Sheets-Sheet 3 V {NVENTOK 1 g/ml Frfnrrwfijyarrzs ATTORNEY.

Patented Mar. 14, 1956 APPARATUS R CONTROLLING s'IL'r' ACCUMQLATIONFrederic R.-Harris, New Ydl'k, N. Y.- Application February 24, 1945,Serial No. 579,633

This invention pertains to a method and apparatus for increasing thedepth of a body of water otherwise and at lower cost than by ordinarydredging; and particularly the water at a site for a floating dry dockemployed in the overhauling and repair of ships.

An important object of my invention is to control the accumulation ofsilt in slips and at other places selected for floating docks, so as tomaintain a depth of water that it always sufficient for the work whichthe dock performs.

Many dry docks are located in rivers that flow through loamy and sandyareas, and then the water carries in suspension with it particles ofsand and loam, termed river silt, which settles on the bottom when thecurrent flow is slowed by an obstruction or a widening of the bed of thestream. This silt usually is in a state of fine subdivision; it isdeposited extensively on the bottom, and the depth of the river soonbecomes materially reduced.

A site for a floating dry dock often requires dredging so that the dockmay be sunk deep enough to receive a vessel in the trough of the dock. Ahole thus excavated at the bottom of the water naturally causes eddiesand precipitation of silt in the depression will immediately set in; anddeposit of silt at a rate of one foot per month under a floating drydock is not uncommon.

Every foot of silt, of course, reduces the available draft of the dockover the keel blocks; and in a few months time the accumulation willlessen the depth of the water by several feet. Hence, dredging mustfrequently be undertaken, or the dock cannot give the service for whichit was designed. But dredging necessitates the temporary shifting of thedock from its berth, and substantial time is lost when the dock is notin use.

In the practice of my invention, however, I have discovered thatdredging and its attendant drawbacks can be avoided, and that thequantity of water which is discharged by the pumps to sink and raise thedock is .suificient to cause a flow of water directly under it to flushaway the silt and keep the bottom of the water free.

of interfering accumulations. Therefore, by periodically sinking thedock and preferably tilting the dock one or two feet along its length,and discharging the full pumping capacity of water for a few hoursoutward toward the centerof the river, the required area of bottom underthe dock will be elfectively deepened and no dredg ing at all will beneeded. I

I Further, though many rivers now can only be utilized for relativelysmall docks, my invention will enable floating dry docks to be locatedin relatively small rivers and serve larger ships than has heretoforebeen feasible.

3 Claims. (01. 114-45) These and other objects and advantages willappear in the. following description, taken with the accompanyingdrawings, and the novel char- I acteristics are defined in the appendedclaims.

. scope and spirit thereof.

On the drawings:

Figure 1 shows how a dock is employed to sweep out silt from the bottomof a river directly beneath it.

Figure 2 shows in outline the bottom of a stream afterward.

Figure 3 illustrates in top plan the pump and pipe connections on theinterior of a dock, as shown above the line 3-3 of Figure 4.

Figure 4 shows the same parts in side elevation.

Figure 5 shows in plan the supply pipes for the flushing system of thedock; and

Figure 6 presents in detail one of the flushing nozzles, viewed from theline 66 on Figure 4.

The same numerals identify the same parts throughout.

The dock has the conventional pontoon hull I and side walls 2. In thebottom of the hull are openings 3, over which are plates 4, which carrythe discharge nozzles 5. The plates and nozzles of course close theholes or openings 3, to prevent leakage; and nozzles discharge jets ofwater 5 below the hull I towards the bottom of the stream 1 in aslanting direction. In action the dock is flooded so as to tilt upslightly at the end which is upstream, or if moored near the shore, theoutshore end; and sunk deep enough for the nozzles to have the bottom Iwithin effective range of their jets 6. Then enough silt can be washedaway to excavate a depression of suflicient depth under the dock, asshown in Figure 2. The hull I has flooding inlets one of which appearsat 8 on one side in Figure 4, for the admission of water to sink thedock; and a discharge port, shown at 9, for the discharge of water whenthe hull is pumped out for raising. The discharge opening is connectedto a pump ID. The pump withdraws through a suction conduit H the waterentering by way of the ports 8. The conduit H is joined to the inletport of the casing of the pump, which is of the centrifugal type, andthe outlet of the pump is coupled toa pipe l2 that supplies the nozzles5. From the pipe l2 a branch pipe !3 I leads to the discharge port ID.The pipes 12 and 13 are controlled by gate valves [4 and it rejspectively; and a gate valve it controls each inlet8.

The'conduit I'Zleads to a header l1 having branch pipes l8. The headerruns substantially parallel to the adjacent wall 2, and the lateralbranch pipes l8 therefrom towards the middle of the hull. Each pipe l8has a number of smaller pipes .l 9 connected thereto; and the pipes 19lead to the nozzles 5. The latter slope downward away from one end ofthe hull and towards the opposite end; that is, approximately parallelto side walls 2. stalled on the other side of the clock.

The dock is sunk as shown in Figure 1 by-open-' ing the ports 8, thedischarge ports 8 being closed. With the dock in position the valves land [6 are closed and the valves 14 are opened and the pumps started todraw the water in the hull through the pipe II and deliver it to thepipe 12. Water is therefore impelled through the pipe l2, header l6,pipes l1 and all the nozzles to wash away silt from the bottom!andfdeepen the water under the clock, as depicted in Figure 2. Thoughthe water may be too shallow at the start, as indicated by the distancebetween the surface S and bottom, a depression 20 of sufiicient depth issoon made.

Thus, dredgin can be dispensed with altogether. The cost of theadditional piping and nozzles is much lower than the regular expensewhich dredging entails.

When the dock is to be submerged it is on the surface, and water thatenters the inlet ports 8 is taken from near the surface where it iscomparatively free from mud and dirt. After sinking, when the openings 8and 9 are closed, the nozzles often require more water than the dockcontains; but now the inlets 8 cannot be reopened because the additionalwater would then be taken from near the bottom and the silt thereinwould foul the interior of the dock. To admit more water recourse istherefore had to gate openings 2! in the outer faces of the walls 2.These openings are controlled by sliding ates 22, havin suitableconnections 23 to hand wheels 24 at the tops of the walls 2. These inletopenings are high enough to take water from near the surface, where itis comparatively free from mud and silt, after the dock is submerged,and the fouling of the inside of the dock is thus prevented. A plentifulsupply of virtually clean water is thus assured as long as the dischargefrom the jets 5 is continued.

The valves l4, I5 and iii are actuated by connections not shown; and thepump can be driven from a suitable source of power. that likewise neednot be illustrated herein.

The dock is illustrated herein as having the usual trough shape, withpontoon hull and side walls, but it of course can be of any design, andbuilt either in sections or as a single structural unit.

The interiors of the dock, of course, are divided into compartments andthe dock can be sunk lower as indicated in Figure 1 by admitting enoughwater to the compartments at the end which is to be depressed.

My copending application No. 717,190, filed December 19, 1946, containsclaims for the method disclosed herein; while the purpose of thisapplication is to protect the construction of the dock. Having describedmy invention, what I believev tobenewis:

1. A floating dry dock having a hulland side walls and a. port at eachsideof the .doclrfadjacent the bottom to admit'water to sink the'do'ck,a discharge port at each side, a power pump at The same arrangement isin each side, piping connecting each power pump to one of the dischargeports, the hull having transverse rows of openings in its bottom, platesover said openings, tilted nozzles mounted in said plates to dischargewater slantwise through the bottom of the dock throughout its lengthtowards one end thereof, piping connecting said pumps to the nozzles,and valves to control said piping, said dock having an-additional inletin the upper part of a side wall to admit additional water to the dockafter sinking, a valve to control said inlet and means extending to thetop of said side wall to control said additional valve.

2. A floating dry dock having a hull and side walls and a port at eachside of the dock adjacent the bottom to admit water to sink the dock, adischarge'port at each side, a power pump at each side, pipingconnecting each power pump to one of the discharge ports, tilted nozzlesmounted in said bottom to discharge water slantwise through the bottomof the dock throughout its length towards one end thereof, pipin con-'necting said pumps to the nozzles, comprising longitudinal headersadjacent the. sides of the dock leading from said pumps, lateralbranches leading from said headers, each branch being connected to agroup of nozzles in transverse alinement, and valves to control saidpiping, said dock having an additional inlet in the uppe part of a sidewall to admit additional water to the dock after sinking, a valve tocontrol said inlet and means extending to the top of said side wall tocontrol said additional valve.

3. A floating dry dock having a hull and side walls and a port at eachside of the dock adjacent the bottom to admit water to sink the clock, adischarge port at each side, a power pump at each side, pipingconnecting each power pump to one of the discharge ports, the hullhaving transverse rows of openings in its bottom, plates over saidopenings, tilted nozzles mounted in said plates to discharge waterslantwise through the bottom of the dock throughout its length towardsone end thereof, piping connecting said pumps to the nozzles, comprisinglongitudinal headers adjacent the sides of the dock leading from saidpumps, lateral branches leading from said headers, each. branch beingconnected to a group of nozzles in transverse alinement, and valves tocontrol said piping, said dock having an additional inlet in the upperpartof a side wall to admit additional water to the dock after sinking,a valve to control-said inlet and means extending to the top of saidside wall to control said additional valve.

FREDERIC R. HARRIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 184,998 'Iassey Dec. 5, 1,876727,059 Balch May'5, 1903 1 749,171 Cunningham Jan. 12, 1904 1,803,191Jennings Apr. 28, 1931 FOREIGN PATENTS Number Country Date 17,855 GreatBritain Oct. 26, 1895

